1. Field of Invention
This invention pertains to a rotary engine with multiple planetary rotors orbiting inside the engine housing. More particularly, this invention pertains to facilitating combustion in such a rotary engine.
2. Description of the Related Art
One type of rotary engine has a main rotor with circular cutouts. Inside each circular cutout is a planetary rotor that orbits the center of rotation of the main rotor. The planetary rotor has faces that sequentially cycle through intake, compression, combustion, and exhaust. Such rotary engines are disclosed in U.S. Pat. Nos. 6,932,047; 7,044,102; 7,350,501; and in patent application Ser. No. 12/041,753, hereby all incorporated by reference. Other rotary engines include those such as the Wankel engine. These engines operate with a different configuration than described herein and experience different problems. In particular, the Wankel-type engines operate with a rotor mounted on an eccentric with the rotor moving within a two-lobed cavity.
The compression and combustion cycles occur sequentially as a face of the planetary rotor passes through top dead center (TDC). At TDC, a face of the planetary rotor defines a trailing volume and a leading volume, with the two volumes divided by a bridge protruding from the housing. The trailing volume contains the compressed gas from the compression cycle. The leading volume becomes the combustion chamber as the planetary rotor continues its orbit past TDC. Isolating the trailing and leading volumes when the planetary rotor passes TDC is difficult.
In order to ensure complete and efficient combustion, it is known to introduce turbulence in the fuel air mixture in a combustion chamber. The configuration of the rotary engine is such that difficulties are encountered in attempting to maintain isolation when needed and to also introduce turbulence when desired.
In the rotary engine, it is desirable to introduce or inject fuel near TDC. At this position, the leading volume is small because of the proximity of the planetary rotor face and the engine housing. It is desirable to keep the leading volume small at the beginning of the combustion cycle and it is desirable to avoid having the injected fuel impinge upon or wet the face of the planetary rotor.